超键(super key):在关系中能唯一标识元组的属性集称为关系模式的超键 候选键(candidate key):不含有多余属性的超键称为候选键 主键(primary key):用户选作元组标识的一个候选键程序主键
1、First Normal Form
https://en.wikipedia.org/wiki/First_normal_form
2、Second Normal Form
https://en.wikipedia.org/wiki/Second_normal_form
3、Third Normal Form
https://en.wikipedia.org/wiki/Third_normal_form
4、Boyce-Codd Normal Form
https://en.wikipedia.org/wiki/Boyce–Codd_normal_form
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